Within the field of food packaging, and packaging of any perishable product, it is of concern to contain the product in a safe way until it reaches the end consumer. Even more so, the end consumer should preferably be able to judge whether the product is safely contained or not before acquiring the product. This is particularly true for the closure of the package. A regular screw-cap closure may be opened and reclosed without causing any visible leakage, yet breaking the hermetic seal may hamper the quality of the product in a dramatic way. This is one of the reasons to why tamper evidence has been introduced. A common tamper evidence is the well known tamper ring, which is torn of the cap as the container is opened for the first time. The functionality of the tamper ring may vary, and there are numerous options available. Also, there are other tamper evidences too, such as lacquer seals and various shrink plastic arrangements, etc.
The closure of a packaging container has to fulfill several demands. It should provide adequate barrier properties, such that liquids or gas does not pass into or out of the container before it is opened for the first time. Also, it should provide adequate resealing properties such that no leakage occurs after the first opening. Additional demands are that it should be easy to open, efficient to manufacture and appealing to the eye.
A thorough overview of the technical field is disclosed in WO2008148764 to SACMI, and it is considered that the skilled person would have no problem in realizing the present invention after studying the teachings disclosed herein combined with the prior art. One example is that the present invention does not discuss moulding of plastic closures. Even if this knowledge is essential for the manufacture of plastic closures, it does not define the present invention in the light of prior art and is therefore considered superfluous for the purposes of disclosing the present invention in a sufficiently detailed manner for the skilled person to practice it.